The present invention relates to the application of a snap fastener to a garment or to an imperforate sheet of material, wherein the snap fastener defines a closure member for the sheet material.
Snap fasteners as normally applied to garments or sheet material include a cap member having fastening means such as prongs extending outwardly thereof and a fastener member that is shaped to receive the prongs for interlocking the cap and fastener members on opposite sides of the sheet material. The fastener member can take the form of a socket, or a stud, depending upon the location of the fastener on the sheet material.
In the application of the snap fastener to the sheet material, it is necessary that the sheet material be maintained in a relatively taut or tensioned position as the cap member prongs are penetrated therethrough for engagement with the portion of the fastener member that is shaped to receive the prongs. Prior to the instant invention, and as best illustrated in the Wolff, U.S. Pat. No. 2,310,007, the application of a snap fastener to the sheet material was accomplished by locating clamping elements in clamping relation on the sheet material wherein an annular area was defined by the clamping elements. Thus, the clamping elements in this prior known apparatus attempted to positively grip the material surrounding the circumscribed area of the sheet material for preparing the circumscribed area to receive the prongs of the cap member therethrough during the application of the snap fastener thereto. One of the objects of the invention in U.S. Pat. No. 2,310,007 was to restrict stretching of the material within the circumscribed area as the prongs penetrated therethrough during the application of the cap member to the fastening member. Although the apparatus as disclosed in U.S. Pat. No. 2,310,007 attempted to retain the material as circumscribed by the clamping elements in firm position and attempted to effectively prevent the sheet material outside the circumscribed area from stretching, the material did tend to give as the prongs penetrated therethrough which resulted in some puckering or wrinkling around the cap member and fastener member following the securement thereof to the sheet material.
As will be described, the purpose of the subject invention is to avoid the wrinkling of the sheet material after the application of a snap fastener thereto and withdrawal of the means for retaining the sheet material in place during the applying operation.